Have you ever spent a day on the beach? Did you put your towel down near the water’s edge early in the morning and come back after lunch and find your towel was wet or gone? What happened to your towel? It probably got caught in the tide. Tides are great bulges of water in the ocean caused by the gravity of the Moon, and Sun. Attracted by gravity, these bulges move around the Earth’s oceans, causing water levels to rise and fall. Typically water will rise for about six hours, followed by six hours of falling water depths. The Sun affects the tides, too, but it is the Moon that affects the tides the most because it is so much closer than the Sun. Watch this video from NASA to learn more about the tides.


Now explore the relationship between the phases of the Moon and tides with this cool interactive tool. This interactive tool allows you to explore how the phase of the Moon and tides are connected. Make sure the Lunar Phase Effect box is checked and set the Maximum Height Change to 5m.  The graph will plot the rise and fall of the tides over an entire Lunar cycle, from full Moon to no Moon and back. Watch the ocean rise and fall as the phases of the Moon changes.


Use your observations to try to answer these questions:

How many times a day (24 hours) does the tide come in and go out?

What is the connection between the phases of the Moon and the height of the tide at high and low tides?


Go here to find answers to these questions and questions of your own about tides.